Gas barrier

ABSTRACT

This disclosure relates to a novel gas barrier for use in connection with rigid conductor coaxial transmission lines. This gas barrier is characterized by a bullet shaped protrusion on which is mounted a conventional insulative disc. The protrusion fits into a mating recess which carries an electrically conductive coiled spring in electrical contact with the protrusion portion to maintain conducting continuity. A resilient O-ring is interposed between the gas barrier insulative disc and the end of the bullet receiving member for gas sealing purposes.

United States Patent [191 Kruger [4 1 Oct. 7,1975

[ l GAS BARRIER [75] Inventor: Jack L. Kruger, Tibbetts l-lill Road,

Goffstown, N.H. 03045 Notice: The portions of the term of this patent subsequent to J uly' 7, 1990, has been disclaimed.

22 Filed: June 2, 1'972 [21] Appl. No.: 258,999

[52] US. Cl. 174/28; 174/21 C; 174/84 S [51] Int. Cl. H01B 9/04 [58] Fieldof Search 174/28, 16 B, 99 B, 21 R,

174/21 C, 21 CA, 22 R, 22 C, 23 R, 84 S; 333/97 R; 339/89 C, 252 R, 253 R [56] References Cited UNITED STATES PATENTS 2,831,047 4/1958 Wadcy 174/22 C 3,319,214 5/1967 Sewell 333/97 UX 3,331,911 7/1967 Whitehead 174/28 X 3,372,226 3/1968 Sewell 17 4/22 C 3,391,243 7/1968 Whitehead c 174/28 3,610,947 10/1971 Stephanides et a1 v. 174/28 X OTHER PUBLICATIONS A Coaxial-Line Support for D-4000Mc, Proc. I.R.E., Jan. 1949, Vol. 37, No. l, p. 97.

Primary Examiner-Arthur T. Grimley Attorney, Agent, or Firm-C. Yardley Chittick 5 7 ABSTRACT 1 Claim, 2 Drawing Figures (III'IIII U.S. Patent Oct. 7,1975

final...

GAS BARRIER This invention relates generally torigidrcoaxial transmission lines and more particularly relates'to gas barriers whichare employedin such rigid transmission'lin'es to maintain a positive pressure 'of dry gas in the space between the outer and. inner conductors thereof.

It is well recognized in the prior art that a gas dielectric rigid transmission line of the type used inantennas should'be 'pressurized-.with dry gas's'ojas to prevent moisture condensation on the interior surfaces and resultant shorting." The, gas barrier devices of the prior artconstruction have been far from effective'or dependable. Broadcast stations allover the countryhave experienced gas leaks due to thefailure of their gas 'bar rier-components, thus resulting ,in system malfunction- The present invention overcomes these priorart deficiencies by providing. a gas barrier :construction which allows part of a bullet connector portion to enter into an adjoining connector portionand at.the;same time to engage in annular compressive contact withacoiled spring. The use .of a coiled spring as'the means'for-insuring electrical continuity between the bullet portion and the adjoining connector-portion; provides a construction in which the axial position of the bullet portion within the coiled "spring-is-not critical. Hence the thickness of the insulative disc through which the bullet portion passes and which holds the inner and outer tubular elements of the rigid line in spaced relation and which also presses against the gas-sealing O-ring, is likewise not critical.

It is, accordingly, among the various objects of this invention to provide an essentially fail-proof gas barrier design and construction which allows on-site installation by non-technical personnel. A further object of this invention is to provide a gas barrier device which can employ an insulative supporting disc of Teflon or the like of non-critical dimensional thickness and yet allow adequate electrical contact between adjacent connecting portions to prevent R. F. burnout.

A still further object of this invention is to provide a gas barrier design and construction which under all circumstances of assembly permits the correct compression of any O-rings used for sealing against gas leaks.

With these and other objects in mind, this invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a partially assembled view of adjoining inner conductor portions of a rigid coaxial transmission line with a gas barrier disposed therebetween and with the outer concentric conductor omitted; and

FIG. 2 illustrates a cross-sectional view taken on line 2-2 of FIG. 1.

Referring now with greater particularity to the drawings, there is illustrated therein my novel gas barrier disposed between and electrically joining two adjoining lengths of rigid inner coaxial conductor portions 11, 12. As shown in FIG. 2, gas barrier 10 is composed of bullet connector portions 15, 16, an electrically insulative supporting disc 13 of Teflon or other suitable nonconductive material, and an elastomeric O-ring 17 of silicon composition or other equivalent material which tends not to distort, lose its elasticity or otherwise degrade over prolonged periods of use.

As illustrated,in,1-FIG.,2, connector portion 16 -has a generally. cylindrical 18 with a recess 19 therein,

Aprotruding' j'snout or bullet portion-'20 with an apersponding recess 21 of connector portion 15. Extending from the bottom.--.of bullet receiving recess 21 is a threaded hole 221An annular reces s 17a in the end face of connector portion IS isadapted to accommodate an elastomeric Orin'g' 17 of silicone for compressive contact against the face of insulative disc 13. Electrical conductivity between connector portions l5, 16 is achieved by the use of an electrically conductive coiled spring 23 carried by a counter-sunk annular recess 24 cut into thesurface of recess 21. This coiled spring is a spring characterized by two broad flat surfacles with rounded ends, wound in a continuous form and generally: silver plated for good electrical conductivity. n16 depth of recess 21 is so proportioned that jwhen spring 24 is seated therein, the surface of its exposed inside diameter protrudes slightly above the surface of recess 2 1 .1Thus, when connector portion 16 is assembled into portion '15, spring 23 ,is yieldably deformed by and maintainsacompressive relation against the surface of bullet portion 20. i v v Thus-in accordance with theforegoing gas, barrier 10 is assembled by inserting spring 23 into annular recess-24, and O-ring l7 into recess 17a; insulative disc 13 is next mounted on bullet portion 20 which, in turn, is inserted into recess 21; bolt 25, dimensioned so as to fit through aperture 31 in bullet portion 20, is threadedly engaged into hole 22, thus compressively joining the component parts together, particularly O-ring 17 against insulative disc 13. Thus, the construction just described assures positive electrical contact between conductor portions along with positive compression of the O-ring even though variations in the thickness of disc 13 may occur.

The outboard ends of connector portions 15, 16 are annularly recessed as to 27, 28 for receiving springs 29, 30, respectively. The outside diameter of these assembled springs slightly exceed the inside diameter of the inner conductor portions 1 1, 12, so that when the conductors are slid into place onto their respective connector portions, each spring will resiliently yield so as to permit its accommodation within the dimensioned confines of its recess, thus providing a firm contact against the inside surface of the connecting inner conductor portion, while at the same time conforming to any eccentricity or out-of-round condition of the conductor to still maintain electrical contact.

I further provide electrically non-conductive slip rings 32 of plastic or other suitable material on the connector portions 15, 16 to overcome any spring popping" clue to careless assembly of the inner conductor portion to the gas barrier. These rings 32 are annularly shaped with a uniform outer diameter. The internal configuration, however, is stepped, i.e., so as to be in part slidable over the end portion of the conductor, as illustrated. Thus, during assembly of the conductors, each by sliding the thicker part to a position ring 32 is initially positioned slid over its corresponding spring 29 and 30 so that when the ends of the conductor portions 11 and 12 are slipped into place within the rings 32, they slide right over the springs Without popping them or otherwise bending or crimping them.

It will be understood that various 'changesinthe details, materials and arrangement of parts-which have,

been herein illustrated in order to explainthe'nature of the invention-may be made by those skilled in the art within the principle and scope of the appended claims.

I claim:

1. In a rigid coaxial transmission line having concentric inner and outer tubular conductor elements wherein spaced insulative discs are used along said line to maintain theinner and outer conductor elements in concentric spaced relation, an improved gas barrier for preventing passage of gas past each said insulative disc comprising an electrically conductive connector having a cylindrical body portion and a bullet portion extending therefrom.

said bullet portion having an axial passage there through, said bullet portion adapted to extend through the insulative disc used to maintain the inner and outer conductor elements of the transmission line in concentric spaced relation,

a cooperating connector portion having a cylindrical recess adapted to receive therein said bullet portion, said recess being of greater depth than the length of said bullet portion extending beyond said insulative disc,

an annular resilient sealing means carried in a circular groove in the end of said cooperating connector "portion for making sealing engagement with said insulative disc, v an axially located and threaded hole at the bottom of the said cylindrical recess in said cooperating connector portion, a bolt extending through the axial passage in said bullet portion and into said threaded hole, for drawing the parts together, whereby said disc will be pressed against said annular resilient sealing means in gas tight relation,

an annular groove around the interior wall of said cylindrical recess, I r v a coiled spring in said annular groove adapted to make electrical contact between said bullet portion and said cooperating connector portion when said portions are assembled,

an outside annular groove in the external surface of the cylindrical body portion from which said bullet extends,

an outside annular groove about said cooperating connector portion,

a coiled spring carried in each of said outside grooves,

and slip ring members slidably carried on said cylindrical body portion and on said cooperating connector portion to cover said coiled springs in the said outside annular grooves and to accommodate the end portions of said rigid inner conductors. 

1. In a rigid coaxial transmission line having concentric inner and outer tubular conductor elements wherein spaced insulative discs are used along said line to maintain the inner and outer conductor elements in concentric spaced relation, an improved gas barrier for preventing passage of gas past each said insulative disc comprising an electrically conductive connector having a cylindrical body portion and a bullet portion extending therefrom. said bullet portion having an axial passage there through, said bullet portion adapted to extend through the insulative disc used to maintain the inner and outer conductor elements of the transmission line in concentric spaced relation, a cooperating connector portion having a cylindrical recess adapted to receive therein said bullet portion, said recess being of greater depth than the length of said bullet portion extending beyond said insulative disc, an annular resilient sealing means carried in a circular groove in the end of said cooperating connector portion for making sealing engagement with said insulative disc, an axially located and threaded hole at the bottom of the said cylindrical recess in said cooperating connector portion, a bolt extending through the axial passage in said bullet portion and into said threaded hole, for drawing the parts together, whereby said disc will be pressed against said annular resilient sealing means in gas tight relation, an annular groove around the interior wall of said cylindrical recess, a coiled spring in said annular groove adapted to make electrical contact between said bullet portion and said cooperating connector portion when said portions are assembled, an outside annular groove in the external surface of the cylindrical body portion from which said bullet extends, an outside annular groove about said cooperating connector portion, a coiled spring carried in each of said outside grooves, and slip ring members slidably carried on said cylindrical body portion and on said cooperating connector portion to cover said coiled springs in the said outside annular grooves and to accommodate the end portions of said rigid inner conductors. 